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DE-102024118338-B4 - Method and system for extracting salt from a layer of earth

DE102024118338B4DE 102024118338 B4DE102024118338 B4DE 102024118338B4DE-102024118338-B4

Abstract

Method (2) for obtaining a salt (3) from a layer of earth (7), wherein - a first pump of a salt extraction system (1) pumps water into a layer of earth (7) (20) in which a salt (3) is arranged, and the pumped water dissolves the salt (3) from the layer of earth (7) to form a brine (5); - a second pump of the salt production system (1) pumps the formed brine (5) into a distillation unit (10) of the salt production system (1) (21) and the distillation unit (10) extracts the dissolved salt (3) from the pumped brine (5) by distillation (22); and - distilled water produced during distillation (6) is pumped into the layer of earth (7) (20).

Inventors

  • Jürgen Mothes
  • Frank Stohler

Assignees

  • AUDI AKTIENGESELLSCHAFT

Dates

Publication Date
20260513
Application Date
20240628

Claims (10)

  1. Method (2) for obtaining a salt (3) from a layer of earth (7), wherein: - a first pump of a salt extraction system (1) pumps water into a layer of earth (7) (20) in which a salt (3) is arranged, and the pumped water dissolves the salt (3) from the layer of earth (7) to form a brine (5); - a second pump of the salt extraction system (1) the brine formed (5) is pumped (21) into a distillation unit (10) of the salt extraction system (1) and the distillation unit (10) extracts the dissolved salt (3) from the pumped brine (5) by distillation (22); and - distilled water (6) produced during distillation is pumped into the layer of earth (7) (20).
  2. Procedure according to Claim 1 , in which the brine formed (5) is distilled at low pressure and/or at low temperature and/or additionally groundwater (4) is extracted (23) and the water is pumped into the earth layer (7).
  3. Procedure according to Claim 1 or 2 , in which the produced distilled water (6) is temporarily stored (24) and heated in a water tank (11) of the salt production system (1) before being pumped into the layer of earth (7).
  4. Procedure according to Claim 3 , in which solar thermal energy provided by a heat exchanger (14) of the salt production system (1) is stored in a thermal storage unit (13) of the salt production system (1) and the produced distilled water (6) is heated by means of the stored thermal energy.
  5. Procedure according to Claim 3 or 4 , in which heat energy provided by an electrically operated heating element (130) of the salt production system (1) is stored in the heat storage unit 13.
  6. Procedure according to one of the Claims 1 until 5 , in which lithium carbonate is obtained as the salt (3).
  7. Procedure according to Claim 6 , in which a mechanical compaction stage (17) of the salt recovery system (1) mechanically compacts the recovered lithium carbonate.
  8. Procedure according to one of the Claims 1 until 7 , in which the salt production system is operated exclusively by means of regeneratively generated electrical energy provided by an electrical energy storage system (12), a solar power system (15) and/or a wind power plant (16) of the salt production system (1).
  9. Procedure according to one of the Claims 1 until 8 , in which the production of the distilled water (6) comprises condensing water vapor produced during distillation on a cold trap of the distillation plant (10) arranged between a vacuum pump of the distillation plant (10) and a low pressure chamber of the distillation plant (10).
  10. Salt extraction system (1) comprising a distillation unit (10) and configured to perform a process (2) according to one of the Claims 1 until 9 to execute.

Description

The invention relates to a method for extracting salt from a layer of earth, in which a first pump of a salt extraction system pumps water into a layer of earth containing salt, the pumped water dissolves the salt from the earth layer, forming a brine, a second pump of the salt extraction system pumps the brine formed into a distillation unit of the salt extraction system, and the distillation unit extracts the dissolved salt from the pumped brine by distillation. The invention further relates to a salt extraction system. Methods for separating a salt from a brine, i.e. an aqueous solution of the salt, in various forms are part of the state of the art and serve to separate the water as the solvent of the salt from the salt dissolved in the water. One purpose of such processes is to extract water from the brine. Thus reveals DE 10 2015 109 119 A1 A device and a method for desalinating seawater. A salt-free distilled water is obtained from the seawater by means of vacuum distillation. JP 2012 091 108 A The document also discloses a device and a method for distilling water. In this method, the water to be distilled is continuously distilled under reduced pressure and heated by solar thermal energy. Also WO 2020 048 577 A1 Disclosure reveals a device for the low-pressure distillation of water. The device uses the weight of the water to be distilled to provide a low pressure in the distillation chamber. On the other hand, such processes can aim to extract salt from the brine. The process described at the beginning is used, for example, in Argentina, Chile, and Bolivia to extract lithium carbonate and is an alternative to the also possible extraction of lithium carbonate through mining, as is carried out, for example, in Australia. DE 15 83 829 A1 and DE 14 58 622 A1 There are known processes in which an unsaturated salt solution is pumped into a mixed salt formation containing sodium chloride and potassium chloride in order to obtain potassium chloride by cooling the brine. The brine produced is usually pumped into large evaporation basins, from which the water evaporates, leaving behind the dissolved salt in the brine. This evaporation releases large quantities of water into the Earth's atmosphere, thus impacting the Earth's climate and accelerating human-induced climate change. Such a process is... DE 34 22 481 A1 known. This negative consequence of brine extraction can be prevented by distilling the brine in a distillation plant instead of allowing it to evaporate. However, water consumption for brine production is very high. Approximately 10 m³ of water are used to produce the amount of lithium carbonate required for an electric vehicle. If the brine is produced using groundwater, the local groundwater level drops as a result of the extraction process. Particularly in the highlands of South America, local groundwater levels are already naturally low. One object of the invention is to propose a method for extracting salt from a layer of earth that is environmentally and climate-friendly. A further object of the invention is to provide a salt extraction system, i.e., a system for extracting salt. An object of the invention is a method for extracting salt from a layer of earth, in which a first pump of a salt extraction system pumps water into a layer of earth containing salt. The pumped water dissolves the salt from the earth layer, forming a brine. A second pump of the salt extraction system pumps the brine into a distillation unit of the salt extraction system, and the distillation unit extracts the dissolved salt from the pumped brine by distillation. The layer of earth is typically located on the earth's surface, i.e., an upper layer of the earth's crust, which can have a thickness of approximately 40 cm. The salt can be present in the earth layer as a crystalline salt or as a mineral salt. The water is a solvent for the salt. The brine is an aqueous solution of the salt. The dissolved salt accumulates in a distillation sump, as is customary. According to the invention, the distilled water produced during distillation is pumped into the soil layer. The distilled water is the distillate produced during distillation. The distillate is reused to dissolve another salt from the soil layer. In this way, on the one hand, evaporation of the distilled water, i.e., its release into the Earth's atmosphere, is prevented, thereby avoiding or at least reducing any negative impact of the process on the Earth's climate. On the other hand, The water is reused cyclically as a solvent, resulting in low consumption of externally supplied water. This low consumption of externally supplied water reduces the environmental damage caused by the process. The method according to the invention is ideally carried out continuously. Preferably, the brine produced is distilled at low pressure and/or low temperature. Low pressure refers to gas pressure and, relative to atmospheric pressure at the Earth's surface (air pressure), is a vacuu